<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>css-loading</title>
</head>
<body>
  <div class="loading">
    <style>
      html, body {
        height: 100%;
        background-color: #f2f2f2;
        margin: 0;
        padding: 0;
      }
      body {
        display: flex;
        align-items: center;
        justify-content: center;
      }
      .loading {
        width: 300px;
        height: 300px;
        margin: 0 auto;
        border: 30px solid #97afe7;
        border-top: 30px solid #4b7beb;
        border-radius: 50%;
        animation: spin 1s ease infinite;
      }
      @keyframes spin {
        from {
          transform: rotate(0deg);
        }
        to {
          transform: rotate(360deg);
        }
      }
      /* 来源于： bilibilli的菠萝power */
      /* https://www.bilibili.com/video/av68116905 */
    </style>
  </div>
</body>
</html>